title: Development and evaluation of NS1 specific monoclonal antibody based antigen capture ELISA and its implications in clinical diagnosis of West Nile virus infection.
abstract: BACKGROUND
  West Nile virus (WNV) is a neurotropic flavivirus that causes viral encephalitis. Recent epidemics of WNV around the world have been associated with significant rates of mortality and morbidity in humans. The early confirmatory diagnosis of WNV infection is important for timely clinical management and epidemiological control in areas where multiple flaviviruses are endemic.
  
  
  OBJECTIVE
  The aim of this study is to develop an monoclonal antibody based antigen capture ELISA for early confirmatory diagnosis of WNV infection with high degree of specificity and sensitivity having no cross reactivity with any of the closely related members of other circulating viruses.
  
  
  METHODS
  The gene coding for the NS1 protein of WNV was cloned and expressed in pET-28a expression vector. Purified recombinant protein was then utilized for generation of mice monoclonal antibody (Mab) and hyper immune sera (HIS) in rabbit. The sandwich ELISA was developed using the rabbit HIS and mice Mab as capture and detector antibody respectively and the results were compared with real time RT-PCR by evaluating 105 suspected clinical samples.
  
  
  RESULTS
  The comparative evaluation of the sandwich ELISA with real time RT-PCR revealed 97% concordance with sensitivity and specificity of 90% and 98% respectively.
  
  
  CONCLUSIONS
  The WN NS1 antigen was detectable in the blood from the first day up to day 9 after the onset of symptoms. The higher sensitivity and specificity of this monoclonal Antibody based sandwich ELISA makes it useful for early diagnosis of WN infection in endemic areas during outbreaks.
authors.affiliation: Division of Virology, Defence Research and Development Establishment, Gwalior 474002, India.
authors.forename: Divyasha
authors.initials: D
authors.lastname: Saxena
authors.forename: Jyoti S
authors.initials: JS
authors.lastname: Kumar
authors.forename: Manmohan
authors.initials: M
authors.lastname: Parida
authors.forename: Rathinam R
authors.initials: RR
authors.lastname: Sivakumar
authors.forename: Ishan K
authors.initials: IK
authors.lastname: Patro
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000302:isolation & purification; D000956:Antigens, Viral / Q000097:blood*; D019411:Clinical Laboratory Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D011817:Rabbits; D012680:Sensitivity and Specificity; D017361:Viral Nonstructural Proteins / Q000097:blood*; D014901:West Nile Fever / Q000175:diagnosis*; D014902:West Nile virus / Q000302:isolation & purification*
chemical_list: D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D017361:Viral Nonstructural Proteins; C531936:nonstructural protein 1, West Nile virus
keywords: Clinical sample; Monoclonal antibody and antigen capture ELISA; West Nile virus